通信类外文文献翻译
使用LabVIEW中的TCP/IP和UDP协议
前言
互联网络协议(IP)，用户数据报协议(UDP)和传输控制协议(TCP)是网络通信的基本的工具。TCP与IP的名称来自于一组最著名的因特网协议中的两个--传输控制协议和互联网络协议。
你能使用TCP/IP来进行单一网络或者互连网络间的通信。单独的网络会被大的地理距离分隔。TCP/IP把数据从一个子网网络或者因特网连接的计算机发送到另一个上。因为TCP/IP 在大多数计算机上是可用的，它能在多样化的系统中间传送信息。
LabVIEW和TCP/IP
你能在所有平台上的LabVIEW中使用TCP/IP。LabVIEW包含了TCP和UDP程序还有能让你建立客户端或者服务器程序的功能。
IP
IP执行低层次的计算机间的数据传送。在组成部分里的IP数据包称为数据报。一个数据报包含表明来源和目的地地址的数据和报头字。IP为通过网络或者因特网把数据发送到指定的目的地的数据报确定正确的路径。
IP协议并不能保证发送。事实上，如果数据报在传输中被复制，IP可能多次传送一个单独的数据报。所以，程序很少用IP而是用TCP或者UDP代替。
UDP
UDP在计算机进程中提供简单而低层次的通信。进程通过把数据报发送到一个目的地计算机或者端口进行通信。一个端口是你发送数据的位置。IP处理计算机对计算机的发送。在数据报到达目的地计算机后，UDP把数据报移动到其目的端口。如果目的端口不是开放的，UDP 将删除数据报。UDP将发生IP的同样的发送问题。
应用程序的UDP的可靠性不强。例如，一项应用程序能经常把大量信息的数据传送到目的地而丢失少量的数据是肯定的。
在LabVIEW中使用UDP协议
因为UDP不是一个TCP似的一个以连接为基础的协议，在你发送或者收到数据之前，你不需要和目的地建立一种连接。相反，当你每发送一个数据报时，由你指定数据目的地。操作系统不会报告传输差错
使用UDP打开功能在一个端口上打开一个UDP插口。同时打开的UDP端口的数量仍依赖于操作系统。UDP的打开的功能返回到网络连接时唯一识别UDP套接字。使用这种连接在子VI程序中就是靠这个套接字。
用UDP编写功能发送数据到目的地，然后使用UDP阅读功能阅读那个数据。每写一个操作要求一个目的地地址和端口。每阅读一个操作包含来源地址和端口。UDP保存你所发送的每一个命令所指定的数据报字节。
在理论上，你能发送任何大小的数据报。然而，你最好不使用UDP来发送大的数据报，因为它不像TCP一样可靠。
当你在一个端口上结束所有通信时，使用UDP结束功能去释放系统资源。
UDP多路广播
你能使用UDP的功能来与一个单独的客户端通信或者通过广播对于所有局域网上的计算机通信。如果你想要传送成倍增加具体的计算机信息，你必须通过客户端列表构建UDP功能反复执行。因为LabVIEW能把数据的作为一个单独的拷贝发送到每个客户端并且保存对收到数据感兴趣的客户端列表，所以运用这种技术建立完全相同的网络交换。
使用多路广播可以在网络上的进行单个的发送端和多倍的客户端之间的通信而不需要保存客户列表或者要求发送端把数据多重拷贝后发送给每个客户端。为了通过多路广播收到数据广播，所有客户端必须加入一个多路广播组。而发送端不需要加入该组。发送端只需规定一个多路广播的IP地址来定义这个多路广播组。多路广播的IP地址范围在224.0.0.0到239.255.255.255中。当一个客户端想要加入一个多路广播组时，它只需预定这个组的多路广播的IP地址。在客户端预定到一个多路广播组之后，客户端收到从多路广播的IP 地址发送的数据。
对于LabVIEW中的多路广播，使用UDP多路广播的打开程序有能力读、写或者读和写UDP 数据。规定TTL为写数据，多路广播地址为读数据，多路广播端口号为读写数据。默认TTL 是1，这意味着LabVIEW仅仅把数据报发送到本地的网络上。当一个发送方收到一个多路
广播数据报时，它消耗数据报的生存时间。如果TTL大于1，发送方把数据报转发到其它数据报。下面的表格说明了当你规定一个TTL的值时，一个多路广播数据报的运行。
0 主机上还存留数据报
1 数据报发送到每个在同一本地网络上已预定那个IP地址的客户端。中枢/转发器和
桥路/开关转发数据报。发送方不转发数据报如果TTL为1。
如果你规定一个值大于1，数据报通过TTL-1层被发送，并且发送方转发它。
参阅在LabVIEW\例子\comm\UDP.llb中的UDP多路广播接受方程序和UDP多路广播发送方程序VI中使用UDP多路广播的例程。
TCP
TCP保证在网络中的可靠的通信，按顺序发送而没有差错，损失或者重发。TCP直到收到一个确认才转发。
系统要求
在使用TCP/IP之前，确认你有必需的要求，这变化依赖于你使用的平台。
(Windows和UNIX系统)TCP/IP。你不需要使用第三种产品连接使用TCP/IP。如果你的网络适当地被构成，LabVIEW没有要求附加的设置。
(Mac OS系统) LabVIEW网络要求打开传送，包括Mac OS 7.5和更新的版本。
在LabVIEW中使用TCP
TCP是一个以连接为基础的协议，这意味着站点必须在传送数据之前建立一种连接。TCP许可多重、同时的连接。
你可以通过等待一种输入的连接或者通过积极地寻求一种与指定的地址连接建立连接。在建立TCP连接时，你必须指定一个地址和该地址的端口。端口范围在0到65,535点之间。UNIX系统为特殊的应用程序保留端口数少于1,024。在一个给定的地址中不同的端口能识别不同的服务。
使用TCP的打开连接功能来与一个指定地址进行积极的连接。如果连接成功，功能返回网络连接的返回数唯一识别那个连接。使用这种连接refnum来访问子VI程序。
你能使用如下技术来等输入连接：
用TCP听程序创建立一个听者并且在一个指定的端口等待一种可接受的TCP连接。如果
连接成功，VI程序返回连接数，地址和远程TCP客户端口。
TCP创建听者功创建一个听者然后用TCP的听者功能上等待的一个听者接受新的连接。
在听者功能上的TCP等待返回你所发送的功能和返回数的同样的听者ID。当你结束等候新的连接时，用TCP关闭连接功能区关闭一个听者。你不能对一个听者进行读写。用第二种技术的优势是你能使用TCP关闭连接功能来取消听操作，这在你想要为了一种连接听而没有超时，但是你想要取消当另一个条件变真时的听时是很有用的。你能在任何时间关闭听程序。
当你建立一种连接时，用TCP读功能和TCP写功能能在远程应用中队数据进行读写。
用TCP关闭连接功能区关闭远程连接。如果没被读的仍保留着而关闭连接，你可能失去数据。当关闭连接时，在你的计算机上使用较高层次协议。在连接被关闭后，你不能再读写它。
TCP和UDP之间的区别
在你想要可靠的数据传输时，TCP是最好的协议。UDP是高性能的无需连接的协议，但是它不保证可靠性。
建立TCP客户端
注意：请参考最近的版本LabVIEW帮助功能对这些指令和功能的细节描述。
完成如下步骤使用TCP功能建立一个TCP顾客。
1.用TCP的打开连接功能来打开一个服务器的连接。你必须规定服务器的因特网地址和服
务器的端口。
地址在网络上识别计算机。远程端口在服务器使用听的计算机上识别一个通信通道。当你建立一个TCP服务器时，你要规定你想要服务器为通信使用的端口。
2.用TCP的写功能把信息发送到服务器上。
3.用TCP的读功能来读发自服务器的信息。你必须规定你想读的字节数。
4.用TCP的关闭功能来关闭与服务器的连接。
请参阅labview\examples\comm\TCP.llb中对单一数据客户端的TCP例程。
超时和差错
当你设计一种网络应用时，应细心考虑失败是如何发生的。例如，如果服务器被毁，确定
如何使每个客户VI程序掌控它。
一种解决方式是确保每个客户VI程序有超时功能。如果发生没能在一定量的时间之后生产结果，客户端继续执行。在继续时，客户端能试图重建连接或者报告出错。如果必要的话，客户端VI程序能关闭应用程序。
建立TCP服务器
注意：请参考最近的版本LabVIEW帮助功能对这些指令和功能的细节描述。
完全如下步骤用TCP功能来建立一个TCP服务器。
1.使用TCP听程序等待连接。你必须规定端口。这个端口必须是客户端试图访问的同一个
端口。
2.如果连接被建立，用TCP读功能从接受到信息的端口读信息。
3.用TCP写功能返回结果。数据必须是一种客户端能接受的形式。
4.用TCP关连接功能来关闭连接。
请参阅labview\examples\comm\TCP.llb中对单一数据客户端的TCP例程。
TCP和UDP例子
请参阅labview\examples\comm\TCP.llb和labview\examples\comm\UDP.llb中用TCP和UDP的VI程序和功能。
Application Note 160 Using LabVIEW? with TCP/IP and UDP Introduction
Internet Protocol (IP), User Datagram Protocol (UDP), and Transmission Control Protocol (TCP) are basic tools for network communication. The name TCP/IP comes from two of the best-known protocols of the Internet protocol suite, the Transmission Control Protocol and the Internet Protocol.
You can use TCP/IP to communicate over single networks or interconnected networks. The individual networks can be separated by large geographical distances. TCP/IP routes data from one network or Internet-connected computer to another. Because TCP/IP is available on most computers, it can transfer information among diverse systems.
LabVIEW and TCP/IP
You can use the TCP/IP protocols with LabVIEW on all platforms. LabVIEW includes TCP and UDP VIs and functions you can use to create client or server VIs.
IP
IP performs the low-level service of moving data between computers. IP packages data into components called datagrams.
A datagram contains the data and a header that indicates the source and destination addresses. IP determines the correct path for the datagram to take across the network or Internet and sends the data to the specified destination.
IP cannot guarantee delivery. In fact, IP might deliver a single datagram more than once if the datagram is duplicated in transmission. Programs rarely use IP but use TCP or UDP instead.
UDP
UDP provides simple, low-level communication among processes on computers. Processes communicate by sending datagrams to a destination computer or port. A port is the location where you send data. IP handles the
computer-to-computer delivery. After the datagram reaches the destination computer, UDP moves the datagram to its destination port. If the destination port is not open, UDP discards the datagram. UDP shares the same delivery problems of IP.
Use UDP in applications in which reliability is not critical. For example, an application might transmit informative data to a destination frequently enough that a few lost segments of data are not problematic.
LabVIEW?, National Instruments?, and https://www.360docs.net/doc/4210272627.html,? are trademarks of National Instruments Corporation. Product and company names mentioned herein are trademarks or trade names of their respective companies. For patents covering National Instruments products, refer to the appropriate location: Help?Patents in your software, the
patents.txt file on your CD, or https://www.360docs.net/doc/4210272627.html,/patents.
342028C-01 ? 2000–2004 National Instruments Corporation. All rights reserved. March 2004
Using UDP in LabVIEW
Because UDP is not a connection-based protocol such as TCP, you do not need to establish a connection with a destination before you send or receive data. Instead, you specify the destination for the data when you send each datagram. Operating systems do not report transmission errors.
Use the UDP Open function to open a UDP socket on a port. The number of simultaneously open UDP ports depends
on the operating system. The UDP Open function returns a network connection refnum that uniquely identifies the
UDP socket. Use this connection refnum to refer to this socket in subsequent VI calls.
Use the UDP Write function to send data to a destination, and use the UDP Read function to read that data. Each write operation requires a destination address and port. Each read operation contains the source address and port. UDP preserves the datagram bytes that you specified for each command you send.
In theory, you can send datagrams of any size. However, you typically would not use UDP to send large datagrams because it is not as reliable as TCP.
When you finish all communications on a port, use the UDP Close function to free system resources.
UDP Multicast
You can use the UDP functions to communicate to a single client (single-cast) or to all computers on the subnet through
a broadcast. If you want to communicate to multiple specific computers, you must configure the UDP functions to iterate through a list of clients. Using this technique creates duplicate network traffic because LabVIEW sends a separate copy of the data to each client and maintains a list of clients interested in receiving the data.
Use multicasting to communicate between a single sender and multiple clients on a network without requiring the sender to maintain a list of clients or send multiple copies of the data to each client. To receive data broadcast by a multicast sender, all clients must join a multicast group. The sender does not have to join a group to send data. The sender specifies a multicast IP address, which defines a multicast group. Multicast IP addresses are in the 224.0.0.0
to 239.255.255.255 range. When a client wants to join a multicast group, it subscribes to the multicast IP address
of the group. After subscribing to a multicast group, the client receives data sent to the multicast IP address.
To multicast in LabVIEW, use the UDP Multicast Open VI to open connections capable of reading, writing, or reading and writing UDP data. Specify the time-to-live (TTL) for writing data, the multicast address for reading data, and the multicast port number for reading and writing data. The default TTL is 1, which means LabVIEW sends the datagram only to the local subnet. When a router receives a multicast datagram, it decrements the datagram TTL. If the TTL is greater than 1, the router forwards the datagram to other routers. The following table lists what action occurs to a multicast datagram when you specify a value for the time-to-live parameter.
Datagram remains on the host computer.
1 Datagram sent to every client on the same local subnet that subscribes to that IP address. Hubs/repeaters
and bridges/switches forward the datagram. Routers do not forward the datagram if the TTL is 1.
Application Note 160 2 https://www.360docs.net/doc/4210272627.html,
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外文文献: Designing Against Fire Of Buliding John Lynch ABSTRACT: This paper considers the design of buildings for fire safety. It is found that fire and the associ- ated effects on buildings is significantly different to other forms of loading such as gravity live loads, wind and earthquakes and their respective effects on the building structure. Fire events are derived from the human activities within buildings or from the malfunction of mechanical and electrical equipment provided within buildings to achieve a serviceable environment. It is therefore possible to directly influence the rate of fire starts within buildings by changing human behaviour, improved maintenance and improved design of mechanical and electrical systems. Furthermore, should a fire develops, it is possible to directly influence the resulting fire severity by the incorporation of fire safety systems such as sprinklers and to provide measures within the building to enable safer egress from the building. The ability to influence the rate of fire starts and the resulting fire severity is unique to the consideration of fire within buildings since other loads such as wind and earthquakes are directly a function of nature. The possible approaches for designing a building for fire safety are presented using an example of a multi-storey building constructed over a railway line. The design of both the transfer structure supporting the building over the railway and the levels above the transfer structure are considered in the context of current regulatory requirements. The principles and assumptions associ- ated with various approaches are discussed. 1 INTRODUCTION Other papers presented in this series consider the design of buildings for gravity loads, wind and earthquakes.The design of buildings against such load effects is to a large extent covered by engineering based standards referenced by the building regulations. This is not the case, to nearly the same extent, in the
机械类外文文献
附：外文翻译 外文原文： Fundamentals of Mechanical Design Mechanical design means the design of things and systems of a mechanical nature—machines, products, structures, devices, and instruments. For the most part mechanical design utilizes mathematics, the materials sciences, and the engineering-mechanics sciences. The total design process is of interest to us. How does it begin? Does the engineer simply sit down at his desk with a blank sheet of paper? And, as he jots down some ideas, what happens next? What factors influence or control the decisions which have to be made? Finally, then, how does this design process end? Sometimes, but not always, design begins when an engineer recognizes a need and decides to do something about it. Recognition of the need and phrasing it in so many words often constitute a highly creative act because the need may be only a vague discontent, a feeling of uneasiness, of a sensing that something is not right. The need is usually not evident at all. For example, the need to do something about a food-packaging machine may be indicated by the noise level, by the variations in package weight, and by slight but perceptible variations in the quality of the packaging or wrap. There is a distinct difference between the statement of the need and the identification of the problem. Which follows this statement? The problem is more specific. If the need is for cleaner air, the problem might be that of reducing the dust discharge from power-plant stacks, or reducing the quantity of irritants from automotive exhausts. Definition of the problem must include all the specifications for the thing that is to be designed. The specifications are the input and output quantities, the characteristics of the space the thing must occupy and all the limitations on t hese quantities. We can regard the thing to be designed as something in a black box. In this case we must specify the inputs and outputs of the box together with their characteristics and limitations. The specifications define the cost, the number to be manufactured, the expected life, the range, the operating temperature, and the reliability. There are many implied specifications which result either from the designer's particular environment or from the nature of the problem itself. The manufacturing processes which are available, together with the facilities of a certain plant, constitute restrictions on a designer's freedom, and hence are a part of the implied specifications. A small plant, for instance, may not own cold-working machinery. Knowing this, the designer selects other metal-processing methods which can be performed in the plant. The labor skills available and the competitive situation also constitute implied specifications. After the problem has been defined and a set of written and implied specifications has been obtained, the next step in design is the synthesis of an optimum solution. Now synthesis cannot take place without both analysis and optimization because the system under design must be analyzed to determine whether the performance complies with the specifications. The design is an iterative process in which we proceed through several steps, evaluate the results, and then return to an earlier phase of the procedure. Thus we may synthesize several components of a system, analyze and optimize them, and return to synthesis to see what effect this has on the remaining parts of the system. Both analysis and optimization require that we construct or devise abstract models of the system which will admit some form of mathematical analysis. We call these models
有关隧道方面外文文献与翻译
A convection-conduction model for analysis of the freeze-thaw conditions in the surrounding rock wall of a tunnel in permafrost regions HE Chunxiong( 何春雄 )， (State Key Laboratory of Frozen Soil Engineering, Lanzhou Institute of Glaciology and Geocryology, Chinese Academy of Sciences, Lanzhou 730000, China; Department of Applied Mathematics, South China University of Technology, Guangzhou 510640, China) WU Ziwang( 吴紫汪 )and ZHU Linnan( 朱林楠 ) (State key Laboratory of Frozen Soil Engineering, Lanzhou Institute of Glaciology and Geocryology Chinese Academy of Sciences, Lanzhou 730000, China) Received February 8, 1999 Abstract Based on the analyses of fundamental meteorological and hydrogeological conditions at the site of a tunnel in the cold regions, a combined convection-conduction model for air flow in the tunnel and temperature field in the surrounding has been constructed. Using the model, the air temperature distribution in the Xiluoqi No. 2 Tunnel has been simulated numerically. The simulated results are in agreement with the data observed. Then, based on the in situ conditions of sir temperature, atmospheric pressure, wind force, hydrogeology and engineering geology, the air-temperature relationship between the temperature on the surface of the tunnel wall and the air temperature at the entry and exit of the tunnel has been obtained, and the freeze-thaw conditions at the Dabanshan Tunnel which is now under construction is predicted. Keywords: tunnel in cold regions, convective heat exchange and conduction, freeze-thaw. A number of highway and railway tunnels have been constructed in the permafrost regions and their neighboring areas in China. Since the hydrological and thermal
10kV小区供配电英文文献及中文翻译
在广州甚至广东的住宅小区电气设计中,一般都会涉及到小区的高低压供配电系统的设计.如10kV高压配电系统图,低压配电系统图等等图纸一大堆.然而在真正实施过程中,供电部门(尤其是供电公司指定的所谓电力设计小公司)根本将这些图纸作为一回事,按其电脑里原有的电子档图纸将数据稍作改动以及断路器按其所好换个厂家名称便美其名曰设计(可笑不?),拿出来的图纸根本无法满足电气设计的设计意图,致使严重存在以下问题:(也不知道是职业道德问题还是根本一窍不通) 1.跟原设计的电气系统货不对板,存在与低压开关柜后出线回路严重冲突,对实际施工造成严重阻碍,经常要求设计单位改动原有电气系统图才能满足它的要求(垄断的没话说). 2.对消防负荷和非消防负荷的供电(主要在高层建筑里)应严格分回路(从母线段)都不清楚,将消防负荷和非消防负荷按一个回路出线(尤其是将电梯和消防电梯,地下室的动力合在一起等等,有的甚至将楼顶消防风机和梯间照明合在一个回路,以一个表计量). 3.系统接地保护接地型式由原设计的TN-S系统竟曲解成"TN-S-C-S"系统(室内的还需要做TN-C,好玩吧?),严格的按照所谓的"三相四线制"再做重复接地来实施,导致后续施工中存在重复浪费资源以及安全隐患等等问题.. ............................(违反建筑电气设计规范等等问题实在不好意思一一例举,给那帮人留点混饭吃的面子算了) 总之吧,在通过图纸审查后的电气设计图纸在这帮人的眼里根本不知何物,经常是完工后的高低压供配电系统已是面目全非了,能有百分之五十的保留已经是谢天谢地了. 所以.我觉得:住宅建筑电气设计,让供电部门走!大不了留点位置,让他供几个必需回路的电,爱怎么折腾让他自个怎么折腾去.. Guangzhou, Guangdong, even in the electrical design of residential quarters, generally involving high-low cell power supply system design. 10kV power distribution systems, such as maps, drawings, etc. low-voltage distribution system map a lot. But in the real implementation of the process, the power sector (especially the so-called power supply design company appointed a small company) did these drawings for one thing, according to computer drawings of the original electronic file data to make a little change, and circuit breakers by their the name of another manufacturer will be sounding good design (ridiculously?), drawing out the design simply can not meet the electrical design intent, resulting in a serious following problems: (do not know or not know nothing about ethical issues) 1. With the original design of the electrical system not meeting board, the existence and low voltage switchgear circuit after qualifying serious conflicts seriously hinder the actual construction, often require changes to the original design unit plans to meet its electrical system requirements (monopoly impress ). 2. On the fire load and fire load of non-supply (mainly in high-rise building in) should be strictly sub-loop (from the bus segment) are not clear, the fire load and fire load of non-qualifying press of a circuit (especially the elevator and fire elevator, basement, etc.
土木工程外文文献翻译
专业资料 学院： 专业：土木工程 姓名： 学号： 外文出处：Structural Systems to resist (用外文写) Lateral loads 附件：1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文 抗侧向荷载的结构体系 常用的结构体系 若已测出荷载量达数千万磅重，那么在高层建筑设计中就没有多少可以进行极其复杂的构思余地了。确实，较好的高层建筑普遍具有构思简单、表现明晰的特点。 这并不是说没有进行宏观构思的余地。实际上，正是因为有了这种宏观的构思，新奇的高层建筑体系才得以发展，可能更重要的是：几年以前才出现的一些新概念在今天的技术中已经变得平常了。 如果忽略一些与建筑材料密切相关的概念不谈，高层建筑里最为常用的结构体系便可分为如下几类： 1.抗弯矩框架。 2.支撑框架，包括偏心支撑框架。 3.剪力墙，包括钢板剪力墙。 4.筒中框架。 5.筒中筒结构。 6.核心交互结构。 7. 框格体系或束筒体系。 特别是由于最近趋向于更复杂的建筑形式，同时也需要增加刚度以抵抗几力和地震力，大多数高层建筑都具有由框架、支撑构架、剪力墙和相关体系相结合而构成的体系。而且，就较高的建筑物而言，大多数都是由交互式构件组成三维陈列。 将这些构件结合起来的方法正是高层建筑设计方法的本质。其结合方式需要在考虑环境、功能和费用后再发展，以便提供促使建筑发展达到新高度的有效结构。这并
不是说富于想象力的结构设计就能够创造出伟大建筑。正相反，有许多例优美的建筑仅得到结构工程师适当的支持就被创造出来了，然而，如果没有天赋甚厚的建筑师的创造力的指导，那么，得以发展的就只能是好的结构，并非是伟大的建筑。无论如何，要想创造出高层建筑真正非凡的设计，两者都需要最好的。 虽然在文献中通常可以见到有关这七种体系的全面性讨论，但是在这里还值得进一步讨论。设计方法的本质贯穿于整个讨论。设计方法的本质贯穿于整个讨论中。 抗弯矩框架 抗弯矩框架也许是低，中高度的建筑中常用的体系，它具有线性水平构件和垂直构件在接头处基本刚接之特点。这种框架用作独立的体系，或者和其他体系结合起来使用，以便提供所需要水平荷载抵抗力。对于较高的高层建筑，可能会发现该本系不宜作为独立体系，这是因为在侧向力的作用下难以调动足够的刚度。 我们可以利用STRESS，STRUDL 或者其他大量合适的计算机程序进行结构分析。所谓的门架法分析或悬臂法分析在当今的技术中无一席之地，由于柱梁节点固有柔性，并且由于初步设计应该力求突出体系的弱点，所以在初析中使用框架的中心距尺寸设计是司空惯的。当然，在设计的后期阶段，实际地评价结点的变形很有必要。 支撑框架 支撑框架实际上刚度比抗弯矩框架强，在高层建筑中也得到更广泛的应用。这种体系以其结点处铰接或则接的线性水平构件、垂直构件和斜撑构件而具特色，它通常与其他体系共同用于较高的建筑，并且作为一种独立的体系用在低、中高度的建筑中。
Manufacturing Engineering and Technology(机械类英文文献+翻译)
Manufacturing Engineering and Technology—Machining Serope kalpakjian；Steven R.Schmid 机械工业出版社2004年3月第1版 20.9 MACHINABILITY The machinability of a material usually defined in terms of four factors: 1、Surface finish and integrity of the machined part; 2、Tool life obtained; 3、Force and power requirements; 4、Chip control. Thus, good machinability good surface finish and integrity, long tool life, and low force And power requirements. As for chip control, long and thin (stringy) cured chips, if not broken up, can severely interfere with the cutting operation by becoming entangled in the cutting zone. Because of the complex nature of cutting operations, it is difficult to establish relationships that quantitatively define the machinability of a material. In manufacturing plants, tool life and surface roughness are generally considered to be the most important factors in machinability. Although not used much any more, approximate machinability ratings are available in the example below. 20.9.1 Machinability Of Steels Because steels are among the most important engineering materials (as noted in Chapter 5), their machinability has been studied extensively. The machinability of steels has been mainly improved by adding lead and sulfur to obtain so-called free-machining steels. Resulfurized and Rephosphorized steels. Sulfur in steels forms manganese sulfide inclusions (second-phase particles), which act as stress raisers in the primary shear zone. As a result, the chips produced break up easily and are small; this improves machinability. The size, shape, distribution, and concentration of these inclusions significantly influence machinability. Elements such as tellurium and selenium, which are both chemically similar to sulfur, act as inclusion modifiers in
冲压模具成型外文翻译参考文献
冲压模具成型外文翻译参考文献 (文档含中英文对照即英文原文和中文翻译) 4 Sheet metal forming and blanking 4.1 Principles of die manufacture 4.1.1 Classification of dies In metalforming,the geometry of the workpiece is established entirely or partially by the geometry of the die.In contrast to machining processes,ignificantly greater forces are necessary in forming.Due to the complexity of the parts,forming is often not carried out in a single operation.Depending on the geometry of the part,production is carried out in several operational steps via one or several production processes such as forming or blanking.One operation can also include several processes simultaneously(cf.Sect.2.1.4). During the design phase,the necessary manufacturing methods as well as the sequence and number of production steps are established in a processing plan(Fig.4.1.1).In this plan,the